Safety-valve for elevators



(No Model.)

P. WRIGHT.

SAFETY VALVE POR BLEVATORS.

No. 389,429. Patented Sept. 11, 1888.

WITNESSES INVENTOR .Re I I Ea/rub@ y By 7a3' .dttorneys 4in- (www, QMMLNW,

N. Pains. Pmemmgnpnr. wamingm. D. c.

PARVIN VRIGHT, OF DENVER, COLORADO.

SAFETY-VALVE FOR ELEVATORS.

SPECIFICATION forming part of Letters Patent No. 389,429, dated September ll, 1888.

Application tiled March 26, 1888. Serial No. 268,588.

To all whom, it may concern.:

Be it known that I, PARVIN VRIGHT, a citizen of the United States, residing at Denver, in the county of Arapahoe and State of Colorado, have invented certain new and useful Improvements in Safety-Valves for Elevators, of which the Afollowing is a specification.

The object of my invention is to produce an improved valve adapted to provide an automatic escape for air from the cylinders of hydraulic elevators.

As is well known, much difficulty has been experienced in running elevator-cars evenly and smoothly by reason of the fact that air inds its way into the hydraulic cylinder and, by reason of its pressure, causes the piston to move after the water-supply has been cut off, and thus the elevator-car is given an additional movement. Thus it sometimes happens that when an elevator-car is` at the top floor of a building, where it should stop, the air in the cylinder operates the piston to send the ear up into the roof. Again, an elevator-car will sometimes drop or fall .by reason of the fact that when the valve in the hydraulic cylinder is open to allow the water to escape the con1- pressed air in the cylinder will rush out much faster than the water, thus causing the ear to drop suddenly, so as to snap the cable that supports the car and letting it drop to the ground.

My improvements consist of an improved valve adapted to be connected to a hydraulic cylinder and operated by hydraulic pressure to open and shut an escape for air from the cylinder.

The accompanying drawing, illustrating my invention, is a vertical section through my improved apparatus.

A indicates a cup or valve-casing provided with entrance-port B for water or air from the hydraulic cylinder. The port B is formed in a screw-threaded end, C, adapted to secure the casing to the cylinder.

D indicates the top cap ofthe casing,prefer ably flanged and screw-threaded, as shown, for attachment to the upper end of the casing. The cap D is provided with a port, E, for the ingress and egress of air. Valve-seats ct b are formed at the port E on the inner and outer sides, respectively, of the cap D.

F indicates a oat, which may be properly (No model.)

Weighted with sand, shot, or other material, F, and is normally heldin the position shown in the drawing by the water which enters from the hydraulic cylinder through the port B and normally stands in the cup or casing A at the level rv, as shown in the drawing. This iioat may be of any suitable construction.

G indicates the safety-valve,preferably consisting oi'a valve-stem, y, provided with valveheads g g2. The valve-head g is arranged to open and close the port E at the valve-seat b, and the valve-head g2 is arranged to open and close the port at the valve-seat a. The valveheads are rigidly connected by the valve-stem g and move coincidently. The valve-stem is prolonged beyond the inner side ofthe valvehead g2 and bears against the top of the float F when the float rises in the cup A. A guide disk or button, gworking in the port E, may be placed on the stem between the valve-heads.

A pair of lever-arms, H H', are pivoted at h to the valve-stem g below the valve-head a. The outer ends of the longer arms of the levers H H are pivoted to upright links I l', which are pivoted at i t" to t-he top of the float F at its edge. The ends h of the short-er arms of the levers H H are turned up or curved, as shown, and adapted to bear at times against the inner side of the cap D.

When water comes up into the cup A from the hydraulic cylinder, the float rises. This actuates the levers H H, and the top of the float F pushes up against the valve-stemg and closes the portata. When air comes into the cylinder, the water will run back out of the cup A, and is replaced by the air which bub bles up through it. When the water lowers by reason of the air-pressure on the top of the cup, the lioat will, by its own weight, drop, causing the levers H H to act as above described on the valve G, so as to withdraw it from the valve-seat a, thus opening the port E and permitting the air to escape. The valve will remain open until the air is exhausted, and as the Water rises again in the cup the doat also rises and closes the valve, as above explained. When the water-supply is cutoff from the cylinder, there is no pressure on the valve, and it, with the float, will drop and close the port E at b, so that no air can enter the cylinder through the cup A.

I claim as of my own invention- IOO The combination of the easing having the air-port and the entrance or water port, the valve consisting of the stem and the two connected valveheads for opening and closing the 5 air-port, the oait, and the lever-arms having connection at their outer ends with the float, jointed between their ends to the valve-stem, and bearing upward at theirinner ends to open the air-port when the float falls, substantially as and for the purpose set forth.

In testimony whereof I have hereunto subscribed my name.

, PARVIN VRIGHT. Witnesses:

L. C. NoRTHRoP, P. C. THoRN. 

